therefore more seldom flooded). It has been found out that the individuals "measure" their height by detecting the amount of energy used for climbing: when artificially loaded, the snails climbed proportionally lower, whereas they climbed higher if the tree trunk was replaced with a smoother surface or if the researchers raised the starting platform. However, it is still a puzzle how the animals are able to predict the water level so far in advance. The difference in body weight caused by the fluctuation of gravity that also causes the tide is probably too low for detection by an organism this small. Chemical cues, such as hydrogen sulfide released from the ground, and acoustic cues, such as infrasound caused by the waves, are probably unreliable indicators of the water level as well, because of the local weather's influence. Every high tide is similar in amplitude to the one before the last, but the snail migration is – statistically speaking – better adjusted to the following high tide than to the one before the last. The underlying process is probably regulated by an internal clock, which can be "confused" by carrying an individual to a lower or a higher part of the coastline. In this case, the animal continues to climb as it would in its original surrounding for several more days or until it gets submerged, then the mechanism "resets" and it is again able to predict the oncoming high tide reliably. Since the cue used by these animals to predict the level of the incoming high tide is still a complete mystery, researchers jest that these snails can foresee the future. References External links Cerithidea decollata - identification guide . A field guide to Kenyan mangroves Potamididae Molluscs of Africa Gastropods described in 1758 Taxa named by Carl Linnaeus